LIMESTONE COUNTY, Alabama - A 35-year-old woman is accused of having sex with a 15-year-old boy who was in her class when she was a substitute teacher at Clements High School.

Karen Dyan Holt of Athens was charged with second-degree rape, second-degree sodomy and second-degree sex abuse. She is being held in Limestone County Jail on $40,000 bond, according to Sheriff Mike Blakely.

Because she was the boy's teacher, additional charges are pending, he said.

"This stems from improper sexual relations with a 15-year-old male," the sheriff said. "Parents of the 15-year-old filed a complaint with Limestone County Sheriff's Office Wednesday, July 16, after becoming suspicious of inappropriate contact between their son and Holt."

The parents called after finding communication between their son and Holt on Facebook, Blakely said. They also said she came to their neighborhood Tuesday night to see their son.

"She drove to his neighborhood and met him behind one of the neighbor's houses," he said "No one home at the time."

When interviewed, both the teen and Holt admitted to having sex behind the neighbor's home, Blakely said. The two met when Holt was substitute teacher in his class during the past school year and ran into each other at Wal-Mart this summer and began talking on Facebook.